Ignition Switch

[Wsullivan71]

I have a 2001 Carver 404 CPMY (Merc 7.4 MPI) with a starting gremlin. When I turn the key, it's a crapshoot on whether or not the engines will start. Here's what happens: I turn the key, the pre-ignition beeps sound loud and clear, I engage the starter and either she starts right up or nothing at all happens. This is happening with both engines. I've bought 2 new batteries to no avail. I've tried battery 1, batter 2, and both on the selector switch to no avail. I've moved/jiggled the clutches to ensure it's not the neutral selective safety switch. It just seems very random. Sometimes they will start right up and other times it will take 4 to 10 tries. It's very unnerving especially when the Admiral is looking over my shoulder. Any ideas? Could it be the 20A breaker above the ignition switch failing? Seems too much of a coincidence for both sides.

[Midnightsun]

I agree, too much of a coincidence both sides. I would take a hard look at 12v positive feed to the helm station or the connection to the starter switches. Both switches probably have a common positive wire. Same goes for the ground or negative 12v if you prefer. That's my best guess, good luck.

[km1125]

Please clarify. When you say "I engage the starter and either she starts right up or nothing at all happens"... Does that mean when you turn the key to start, NOTHING happens, or you turn the key to start and the starter engages and spins but the engine does not start?

And this happens on BOTH engines at the same time or just ONE engine does this or EITHER engine will do this at various different times?

[bud37]

Have a look at the starter relays on the engines...they get corroded inside, they can be cleaned but don't cost much to replace if bad.....common problem....keep spares.

[chpsk8]

I had a similar issue involving one motor only though. There's a signal wire that goes from the ECU to the ignition. In the harness going to the helm there was a quick connect that I'm assuming was installed to allow the helm to be plugged in when the flybridge was installed after transport.
That connector had corroded and would only work intermittently. Bypassed the connector with a splice and I've never had a problem since. (knocks wood).

If it's both motors you'll be looking for something shared such as a ground or power line. Connections are always a good first check. Remove, clean and reinstall ground connections is never a bad idea.

[Wsullivan71]

So to clarify, sometimes nothing happens, the starter does not engage at all. I turn the key, get the 2 beeps, then when I turn the key to engage the starter, nothing happens. It's random to both engines. Sometimes one will start on the first try and the other might take 5 tries over the course of 20 minutes.

Thanks Bud37, the starter relays would be an easy fix. Any idea where they are located?

I'll also check the 12V positive feed to the helm station. Thanks Hans.

[bud37]

Just google mercruiser starter relays for your year engines and compare the pics to what you see on the top of your engine, not sure exactly where yours are, but have a look around , check out some connections and grounds as others have mentioned while you are there, they are also possibilities especially if there was work recently performed down there.....won't hurt to get familiar with what you find there.......good luck

[Dewmyster]

I have the same problem with my 1998 Voyager with 7.4 MPIs. Thought is was a starter switch failure. Had a spare switch and replaced....all was fine until it was time to winterize. Turn the key and nothing. Checked all starter connections and still nothing. On the bridge turning the key until it starts! Can't wait until spring to check behind the console. I had Chart plotter issue and pulled out and replaced with a new SIMRAD. Bet I jigged the inline connector! Will let you all know around May 15th.

[Viper]

Could be a few things but the most common cause is the slave solenoid. Usually mounted on the front of the engine starboard side if the engine faces the bow. Sometimes there is a red breaker there depending on the model/year. Have a listen there while someone turns the key on and off. If you hear the solenoid clicking, it's either a bad slave or something further down the circuit like the starter. A test meter really helps here to check the load side of the solenoid if it's clicking. This will tell you if it's closing the load side/circuit. Make sure your connections are clean and tight.

[Wsullivan71]

Thanks everyone, appreciate all of your tips! I will let you know what I find once I get back to the boat next month.